1. Field of the Invention
The present invention relates generally to the field of classification. More particularly, the invention relates to classification based on data-driven techniques, especially classification of the state of activity of a person based on sensor readings.
2. Brief Description of the Related Art
One of the significant challenges in medical monitoring and testing of humans is posed by the need to measure and monitor humans in a consistent state, in order to draw conclusions from the measurements. For example, when measuring blood pressure to assess health, customary protocol dictates a person must be seated and resting for a period of minutes prior to taking the measurement, and the armband must be held out at heart level. When monitoring patients in an intensive care unit, patient movement is likely to often set off alarms on monitoring equipment, which works well only under extremely stable conditions. Measurements of patient vital signs need to be taken at appropriate conditions in order to optimally report the health of the patient. More broadly speaking, with the advent of wearable sensor technology for real-time monitoring of human health, it becomes imperative to filter down the collected data to only those measurements gathered during certain states of activity, to provide meaningful data.
Human activity classification also has important roles in other applications. Technology that monitors the wakefulness of a driver can aid in alerting the driver when they begin to doze off. Sensors may more appropriately convey the condition of a soldier in the battlefield if different states of activity can be discerned.
Determining the state of activity of a person based on sensor data poses a substantial problem of highly dynamic multivariate data. It is extremely difficult to come up with reliable means of determining the state of activity of a person. Mostly, rules are applied to raw data to determine activity state, but these rules can be difficult to apply across the variety of personal weight, height, and other differences. What is needed is a reliable way of determining activity state from the sensor data obtained from a subject human.